And now, at this critical moment, a new and thrilling peril confronted the trio.
Suddenly Frank saw a long, sinuous body flash through the water some fifty feet distant.
He saw its outlines and its shining silver scales, and at once recognized a deadly foe.
“A swordfish,” he muttered.
Then he made a motion of warning to the others.
They leaped out of the way, but were not a moment too soon.
The huge fish, with its keen lance of sharpest bone, had made a dive for them.
As it dodged past him Frank struck at it with his ax.
The blow nearly severed one of the fins of the huge fish and a cloud of blood spurted into the water.
But instantly the swordfish turned and came again to the attack.